This invention relates to a process for the production of 2-acetyl-1-pyrroline compounds and compositions containing the same.
U.S. Pat. No. 4,522,838 (Buttery, et al.) describes a process for the production of 2-acetyl-1-pyrroline. This process comprises catalytically reducing 2-acetyl pyrrole for 15 hours under a hydrogen pressure of approximately 0.7 bar, to obtain (1-hydroxyethyl)-2-pyrrolidine as an intermediate product, and oxidizing the intermediate product obtained with silver carbonate under reflux in benzene, again over a period of 15 hours. The 2-acetyl-1-pyrroline is then isolated by gas phase chromatography using a capillary column 2 meters in length and 6.4 mm in diameter. The 2-acetyl-1-pyrroline thus obtained has a purity of approximately 95%, but can only be produced in small quantities at a time, due mainly to the purification of the compound by gas phase chromatography. In addition, the 2-acetyl-1-pyrroline is unstable and has to be stored at a temperature preferably below 0.degree. C., which makes it difficult to use, particularly on an industrial scale.
Another process for the production of 2-acetyl-1-pyrroline from pyrrolidine is known from European Patent Application Publication No. 436 481, but does not solve the problem in question.